[en] A short review is given of some problems of the nucleus theory which arise in connection with investigations on various manifestations of the shell structure in fission and numerous attempts to correct or refute the theoretical approach known as a method of shell corrections or a micro-macroscopic method. A shell or zone structure in nuclei is considered. The problem -what are a potential of shell model and a nucleus form are investigated. The continuum and drop energy problem is discussed. The particularities of the nucleus theory where the role of the shell structure is particularly remarkable as well as the development of more technical aspects are discussed. As a general result of numerous calculations of shell corrections in deformed nuclei the question arises why the shell structure of nucleon single-particle spectra is such a widespread phenomenon or what is a shell or zone structure in nuclei